MOVEMENTS OF ATMOSPHERE GULDBERG AND MOHN 245 



From the last equation we obtain 



(7) 



a T 2 cu sin 6 



For the ascending currents the value of w is positive and the angle 

 a falls between 270 and 360 , that is to say, the direction of the axis 

 X is between the west and the north. 



By eliminating w between equations (5) and (7) we shall find 



u = — 2 co cos sin a (8) 



The maximum value of u occurs for 6 =» o° and then we have 

 a = 270 ; for T =' 273 we shall find u = i.2 m . 



For example let 8 = 45, ° T = 273 and w = 1 meter, we shall 

 find a — 309°.5 and u = 0.64 111 . 



The inclination of the ascending current to the vertical being i, 



we have 



u 

 tang i = — = 0.64, 



whence i = 32 37'. 



If the height of the current was ioooo m , the center of the baromet- 

 ric maximum in the upper strata would be moved 0.64 kilometer, 

 or about 0.06 degree of a great circle from the vertical passing 

 through the barometric minimum at the surface of the earth. We 

 come therefore to the conclusion that in cyclones the current axis is 

 inclined backward by the action of the rotation of the earth, but so 

 little that we can neglect the effect of this inclination. 



